A spokesman from the Met said: "The contract was terminated on the basis of the supplier's failure to deliver the command and control system in accordance with the contract, including its failure to deliver in time for the originally planned October 2015 go-live date.

"There was no prospect of a finished product being delivered before the expiry of the contract term on 18 March 2016."

Northrop Grumman has disputed the Mayor's Office for Policing And Crime (MOPAC's) right to terminate the contract. MOPAC stands by its decision, and is seeking immediate repayment of milestone payments from Northrop Grumman, said the Met.

"MOPAC is also minded to pursue a claim against Northrop Grumman for costs and damages arising from the supplier's failure to deliver a command and control solution in accordance with the contract.

"The decision to terminate does not affect the MPS' existing command and control system, which remains in normal operational use. The existing system is undergoing further modernisation, and the MPS is also looking at alternative options to meet its longer-term operational requirements."

The contract was part of the Met's Total Technology strategy. The plan also involves carving up its mega contract with Capgemini and handing it to multiple outsourcers instead.